I saw a RealAudio clip of Stu Hamm explaining his style and he said a little bit about his rig. He said he plays his fender urge II through a hartke rig. I don't remember him saying anything about effects so I'm guessing what JMX had to say is correct.

The new album, "outbound" was recorded by Stu plugging into an ART Tube MP mic pre and then straight into pro-tools via a computer. It was done at and by a duo known as Youth Engine in San Francisco. All the 'verb, delays, vibrato (like on Charlotte's Song) and such were added post production. (I got all this from Stu via Bass Player magazine). he would occiasionly put a boss bass OD and Digitech Whammy pedal in front. No amps, or boards were used during the recording. Bass>Tube MP>computer. That's it!
Live he uses no fx..tho I hear he's been messing with the whammy pedal and OD, so I hear.
Max

That would be the Zoom B9.1ut - he makes use of the Z-pedal to control the delay feedback and something else at the same time.

Stu is one of these guys that has a used a lot of gear over the years, and endorsed a lot too. He endorsed Korg effects for a while, the Pandora and a couple of other multi's had Stu designed patches. He was a Hartke man for years, then started endorsing the Peavey Bam briefly before switching back to Hartke. Then there's the basses themselves, Kubicki, then the signature Fender Urge and Urge II, now Washburn.

I also seem to recall an internet video of him giving a rig walkthrough from the Satriani Live in San Fransico concert. IIRC he had some kind drive, delay and a bass whammy for octave.

So I think the lesson to be learnt here is that you don't need specific effects or gear to get his tone. I hate to say it, but it's all in the fingers! Well, to a certain extent. You should be able to cop his tone with any decent gear (P/J bass would be good for a start), and maybe a multi for the more exotic sounds.